Improvement in coffer-dams



vent the ingress of water when the water is UNrren Santas Farma Ormea..

AARON GILMORE, OF BUFFALO, NEW YORK, ASSIGNOR TO HIMSELF, B. H. AUSTIN, JR., ANI) DOLPHUS S. AUSTIN, OF SAME PLAGE.

IMPROVEMENT IN COFFER-DAMS.

Specification forming part of Letters Patent Noi 53,9!9, dated April 10, 1866.

To all lwhom t may concern Be it known that I, AARON GILMORE, of the city of Buffalo, county of Erie, and State of New York, (assigner to myself, BENJAMIN H. AUs- TIN, Jr., and DoLPHUs S. AUs'rIN, ofthe city of Buffalo aforesaid,) have invented a new and Improved Portable Cotter-Dam 5 and I do hereby declare that the following is a full and exact description thereof, reference being' had to the accompanying drawings, making a part of this specification, in which- Figure I is a longitudinal section. Fig. II is a transverse section. Fig. III is a top plan.

Letters of like name and kind in the drawings refer to like parts in each of the gures.

The nature of this invention relates to Inaking a cotter-dam which may be iioatcd -from place to place upon the water and lled with water and sunk at any place desired, and a free dry space obtained within for the erection of an abutment or pier, and the water therein then discharged by pumps, and the dam will again float and clear the abutment or pier and be in a condition to be again used at another place.

To carry out and realize the purpose of my invention, I make a' structure which, in its exterior outlines, somewhat resembles a fiatbottomed boat with an oblong open area in the center within which to construct an abutment or pier when it is placed in the bed of the stream for use. This structure is represented at A in the drawings. It is made with double walls and hollow or with bulk-heads or water spaces within its walls, as shown at A', which spaces may be filled with water for the purpose of sinking' .the structure onto the bed ot' the stream where lthe pier is to be built. Valves are provided for admitting water into these spaces, which are shown at B. These valves are to be opened to admit water and closed when the water-spaces are filled, so as to prepumped out. The rear end of this structure is made adjustable, so that it may be opened and shut like a lock-gate, or so that it may be raised up or removed to allow the structure to be floated away after the pier or abutment' is built without contact with the abutment.. This movable end piece is shown at A2. Its particular construction and adjustment is not important, so that the main idea of raising or opening it sufficiently to clear the abutment is observed. In some cases the rear end could be made stationary, like the side walls; but such stationary end would render the structure less convenient in practice, for the reason that it would be necessary to lift it over the abutment when bilt in order to be iioated away without striking the abutment.

The front end of the structure is made tapering, like the bow ot' a boat, and in case a gate is used for the rear end it may also be made slightly tapering. Holes are made through the deck, as shown at O, for the insertion of pumps for pumping the water out when the abutment is completed.

Figs. I and III represent the structure as sunk and standing upon the bed of the stream. It will be noticed that between the abutmentspace D and the inner walls of the structure there is formed a space, E. This is for the purpose of driving plank into the bed of the stream, in case the bottom ofthe same is sand or gravel, to facilitate packing the structure to the bottom of the stream, and in case there is rock bottom then they are to be litted thereto. These planks are shown at F.

Clay or water cement or other suitable composition is put in between the planks, as shown at g, and tamped down, so as to form a watertight packing as between the bottom ofthe structure andthe bed of the stream, and thereby prevent water from flowing into the abutment-space.

H represents studs or posts made fast to the inner wall of the structure for the purpose of' supporting the boards or planking I of the abutment space. The thickness ot'these studs forms a sufficient space to receive the planks and cement for packing. The studs are tapered or shortened at the bottom, so that the 'cement will form a continuous layer around the abutment-space.

In Fig. II is represented a false bottom, J, made of timbers and plank, to cover the abutment-space D. This will be found serviceable in many cases as a foundation for the abutment to stand upon where the bed of the stream is sand or gravel. This bottom is held in place by the chains K and windlass-drums L. A rubber packing, m, is used between the overlapping part and the bottom of the structure in order to make the connection Watertight.

The pier or abutment N is shown as standing upon the false bottom in Fig. II. A portion of it may be built before it is placed on the bottom ot' the stream. Then the abutment is completed the chains are unhooked or disconnected from the false bottom, so that the structure may be oated away, leaving the pier standing in place. The pier or abutment N, Fig. I, is shown us standing` upon the bed of the stream.

Considerable variation may be made in the AARON GILMORE.

Witnesses:

B. H. MUEBLE, W. H. FoRBUsH. 

